Slag crushers are used for crushing lumpy mineral slags and unburnt residues, as they are produced in combustion processes or in the gasification of coal.
From DE 42 20 265 C1 there is known an apparatus for producing gas to be used in firing plants.
The apparatus comprises a reactor housing that is water-cooled with respect to its wall portions. Inside the reactor housing there is disposed a stepped reactor bottom carrying the material to be gasified, which reactor bottom is divided into several stationary portions and between the same into incorporated movable portions. Supply lines for the gasification medium are associated to the movable portions. In direction of movement of the material to be gasified behind the reactor bottom there is provided an ash discharge including a discharge worm having crushing elements. Above the lower end of the reactor bottom there is provided a water-cooled rotating slag crusher with water-tooled crushing teeth provided on its periphery. Below the lower end of the reactor bottom there is disposed an ash collecting chamber with a discharge worm which likewise has crushing elements on its periphery.
In the case of a slag crusher developed by the applicants for oil or coal gasification plants, which is disposed at the outlet of a radiation cooler or a gasification reactor with chilling or quenching section, the crushing operation takes place in a water bath under the process pressure. Corresponding to the process conditions, the housing of the slag crusher is pressure-proof. The passage of the drive shaft of the cutting knives through the pressure housing has been effected by means of a pressure-tight stuffing box sealing system with sealing water.
The actual crushing operation inside the pressure housing is performed by rotating cutting knives. The stationary cutting knives serve as shoulder or thrust bearing when crushing the large slag lumps by means of the knives disposed on a rotating shaft.
A disadvantage of this slag crusher is the centric arrangement of the shaft in the pressure housing with the rotating knives between the radial and axial inlet baffle plates disposed on both sides and the stationary knives disposed on one side of the radial baffle plates.
The uncrushed and too large slag lumps pile up above the rotating knives and are again and again pushed upwards through the too small opening between the baffle plates provided on both sides and are not supplied to the knives. There is a pile-up of material above the rotating shaft, which leads to an interruption of the flow of material and impairs a controlled crushing and removal of slag.
It is therefore the object underlying the invention to arrange the cutting tools such that both small and large slag pieces are seized completely and a controlled crushing and removal of the slag from the slag crusher is effected.